/**
 * Created by lenovo on 2017/8/16.
 */
(function(win,doc){
    win.onresize = function(){
        change();
    };
    change();
    function change(){
        var oFs = doc.documentElement.clientWidth/640*20;
        doc.documentElement.style.fontSize = oFs + 'px';
    }
})(window,document);